var idx=102;
var ShutterOpen = "cmnd/ekran/shutteropen1";
var ShutterClose = "cmnd/ekran/shutterclose1";

if (idx==msg.payload.idx)
{
    if (msg.payload.nvalue===0)
    {
        return {topic: ShutterOpen, payload: ""};
    }
    else if (msg.payload.nvalue==1)
    {
        return {topic: ShutterClose, payload: ""};
    }
}